The pontificate, which is permanent, and the apostolate, which is temporary, were, for a time, united in the same persons. Both were directly conferred by Jesus on His Disciples.
To Peter, Jesus gave the supreme pontificate, the supreme pastorate, over all the sheep of the fold. From Peter, in whom it had resided inits highest form, it would have been normal for the pontificate to descend into the body of the Church in a derived form, that of the episcopate. But God, anticipating on the operation of His own laws, can produce immediately what, in the regular course of things, would come about as a normal consequence; for instance He might create a tree already laden with fruit. So it was that Christ acted with His Apostles. He conferred on the Apostles the episcopal power of jurisdiction which, normally, should descend to them from Peter whose sheep they were. He conferred the apostolate on the Twelve directly, and not through Peter. “And it came to pass in those days that he went out into a mountain to pray, and he passed the whole night in the prayer of God. And when day was come, he called unto him his disciples; and he chose twelve of them whom he also named Apostles” (Luke 6:12-13). Now this apostolate would necessarily carry with it, as soon to be exercised, both the episcopal power of jurisdiction and the episcopal power of order.
Thus, then, Jesus gave directly to Peter the supreme pontificate or Papacy, and to the other Apostles the dependent pontificate or episcopate. Furthermore, He gave directly to the Twelve the privilege of the apostolate. In the first days of the Church, on the morrow of Pentecost, the permanent jurisdiction existed therefore whole and entire; but it was hidden as it were within the extraordinary jurisdiction; somewhat as a flower, already preformed, remains protected and hidden for a time in the enveloping folds of its calyx.
All the Twelve had the apostolate - their untransmissible privilege. Peter had the Papacy besides, and the others the episcopate - their transmissible dignity. St. John, St. James and St. Paul, for example, considered as Apostles - that is, as having power over the universal Church for its foundation - could not have successors, for the Church could not be founded twice. But considered as bishops, that is as simply possessing the plentitude of the power of order, and, in dependence on Peter, jurisdiction over a particular portion of the Church, they could have successors. Should these successors separate themselves from Peter they might indeed, by sacramental transmission, retain the fullness of the power of order. But they would at once lose the sole jurisdiction the Apostles could communicate - that is to say a jurisdiction to be exercised in dependence on that of Peter - and in this respect it would be of little use to them to occupy a see once founded by the Apostles, or to be, in virtue of mere historical continuity, the Apostles’ successors.